ElectrostaticsMedium

Question

The electric potential as a function of $x,y$ is given by $V = 5\left( x^{2} - y^{2} \right)V$. The electric field at a point $(2,3)m$ is $\_\_\_\_$ V/m.

Options

A.$( - 20\widehat{i} + 30\widehat{j})$
B.$(20\widehat{i} + 45\widehat{j})$
C.$( - 4\widehat{i} + 6\widehat{j})$

Solution

Sol. [Key Concept: $E = - \nabla\ V$ with $V = 5(x^{2} - y^{2})$ gives $E_{x} = - 10x,\ E_{y} = 10y$; at $(2,3)$ this is $( - 20,30)$ V/m.]

$$V = 5\left( x^{2} - y^{2} \right)V$$

$$\begin{matrix} & \varepsilon_{x} = \frac{- dv}{dx} = - 10x\widehat{i} \\ & \varepsilon_{y} = \frac{- dv}{dx} = + 10y\widehat{i} \Rightarrow \varepsilon(2,3) = - 20\widehat{i} + 30\widehat{j} \end{matrix}$$

Create a free account to view solution

View Solution Free
Topic: Electrostatics·Practice all Electrostatics questions

More Electrostatics Questions